What should i do to beat elite four?

I have trained my pokemon in victory road and have get freaked up by graveler and golbat. I have trained with elite 4, and sometimes tried to beat them all, but it never works! This is my team now:

Lugia lv. 65
extrasensory-Punishment-Hydro pump- Aeroblast

Ampharos lv. 35 (not trained fully jet)
ThunderShock-Thunder Wave-Charge-Discharge

Swinub lv. 31 (still under training)
Powder snow-Ice shard-Icy wind-Mud bomb

Gyrados lv.43
Dragon rage-Ice fang-Hydro pump-aqua tail

fearow lv. 55
Drill peck-roost-fly-areal ace

Who should i remove? I can beat all in elite 4 with lugia, but when i came to the last one, i never win. (once he just had one pokemon again but he used thunder on my fearow :c )

i went through the elite four without potions at first to see what pokemon they had then i found out what all the pokemon's weakness then got the pokemon well i had most of them then i bought moves that can really do damage on there pokemon then i went into the victory road probably 4 or 5 times. you should get all of your pokemon to the same level. also u should get an eevee at the goldenrod city bills house cause they can evolve into a lot of types which is good cause a dark type will help you and when you go back to the elite 4 bring potions and and have a full team i hoped i helped any way possible

level up ampharos to lv.50 and use it against lance first by paralyzing his pokemon. then drop swinub and get a lapras in the union cave (you need surf and it has to be done on a friday other wise he won't be there,he will be at lv. 20 so you will have to train him alot. but when he is at a lv.50 he is really strong. teach it blizzard,surf,phscic, and body slam)let go of hydro pump and teach your gyarados surf,blizzard,dragon pulse, and hyper beam.drop fearow and get a dratini in the dragon's den. then level it up to lv.55 and it will be a dragonite. teach it draco meteor,thunder,blizzard and surf. that WILL get you through the elite four

I would definitely level up your Pokemon more. Especially Ampharos and Swinub. Get them to the point of the others.